Trouble activating an Ooma DP1 desk phone

I have an older Ooma office system, bought in late 2013. I have used it for over 7 years without major difficulties, and feel it works well for my small doctor’s office.

I recently purchased an Ooma wireless desk telephone (DP1) and have been unable to activate it. When I press the PAGE button on the central unit, I get a message that my base unit is not supported and to call 1-888-711-6662. When I called this number, I was eventually transferred to hardware support. The nice and helpful person there said Ooma would send a new unit. I assumed a newer base unit, but what arrived was another DP1 phone, which also refuses to pair with my older base unit.

I suppose I need a new base unit, not another DP1. Are there older base units that are not compatible with the DP1?

Do I need to purchase a new base unit? Or perhaps Ooma can sell me a less expensive refurbished one?

Please help.

Russell Barr MD